1. Field of the Invention
This invention relates generally to livestock trailers (e.g., horse and cattle trailers), and more particularly, but not by way of limitation, to welded metal livestock trailers which include side walls formed of extruded metal slat units.
2. Background of the Invention
Horses, cattle and other livestock are commonly transported from one location to another in specially constructed trailers which include side walls, roofs, loading gates or doors and coupler assemblies. The dimensions and features of such trailers vary widely depending upon the type of livestock involved and the specific end-uses for which the traillers are designed. For example, horse trailers range from single-horse, standard hitch trailers to multi-horse, gooseneck hitch trailers that include living quarters for the horse attendant(s).
The side walls of many livestock trailers are formed using sections or slats ("slat units") that have been extruded as a one-piece unit out of metal (e.g., an aluminum alloy). The advantages of using extruded metal slat units to form the side walls of a livestock trailer are numerous. For example, slat units formed of a metal such as an aluminum alloy are strong enough to support the livestock yet relatively lightweight which enhances the mobility of the trailer. Aluminum alloys that have good strength, corrosion resistance and machinability are readily available. The extrusion process is relatively inexpensive and allows slat units to be formed in a variety of shapes and sizes. The slat units are durable and have good welding characteristics. The slat units are directly welded to the side posts of the trailer from the inside of the trailer thereby allowing the side walls of the trailer to be easily and readily assembled. The slat units are typically corrugated to provide maximum strength thereto.
Unfortunately, although the ability of the slat units to be welded directly to the side posts of the trailer is an important advantage, the welding process creates heat tracks or weld marks ("weld marks") that show up on the exterior surfaces of the slat units and hence the outside of the trailer. The nonaesthetic nature of the weld marks decreases the value of the trailer in many respects. There is a need for a way to prevent the weld marks from showing up on the exterior surfaces of the slat units.